1. Field of the Invention
The present invention relates to gas emission sample containers for collecting gas emissions from motor vehicles and, more specifically, to fittings and tube apparatus for use in such gas emission sample containers.
2. State of the Art
Expandable, sealed containers or bags are employed for collecting and temporarily storing gas emissions from motor vehicles before the collected emissions are analyzed by suitable test equipment. Such containers are expandable to a constant volume to collect a known quantity of gaseous emissions.
Typically, a plurality of such containers, such as six containers, are connected through suitable conduits, valves, etc., to a test apparatus to collect separate quantities of gas emissions from a vehicle and from ambient atmosphere. Samples of emissions from a motor vehicle under test are collected in the sealed containers as the motor vehicle is operated according to a prescribed test schedule corresponding to various engine operating conditions.
The expandable containers include a fitting sealingly mounted in each container which is connected to the test apparatus to receive gas emissions from the vehicle under test. The fitting directs the gas emissions into the container for storage, as well as enabling the stored gas contents to be evacuated for subsequent analysis. The fitting and the sealed container are made of a chemically inert material, such as a fluorinated carbon plastic, i.e., plastics sold under the registered trademarks TEFLON and/or TEDLAR.
In order to prevent wrinkling of the container when evacuated of gas and to insure complete inflation of the container to a constant volume without internal dead spots, small diameter, hollow conduits or tubes are disposed within the sealed container and connected in fluid flow communication with the fitting. The conduits have apertures formed along their lengths to draw gas from different parts of the container to prevent stratification of the gas within the container and to insure thorough mixing of the gas. Such conduits have been provided in a variety of shapes, such as a plurality of circumferentially spaced, straight segments, curved segments, etc.
However, the fittings employed in such gas emission sample containers have heretofore had a generally spherical shape with internal bores connected in fluid flow communication with a port having an externally mounted hollow connector attached thereto. It is felt by those in the industry that the size of the spherical-shaped fitting and the relatively large diameter of the tubes disposed within the sealed container create dead spots in the container adjacent the fitting which prevents complete inflation of the container and/or complete evacuation of the gas from the container. This leads to erroneous emission test results since the quantity of gas varies from container to container.
Thus, it would be desirable to provide a fitting and tube apparatus for a gas emission sample container which overcomes the above-described problems associated with prior art fitting and tube apparatus. It would also be desirable to provide a fitting and tube apparatus for a gas emission sample container which substantially eliminates dead spots within the container during the inflation and evacuation of the sealed container. It would also be desirable to provide a fitting and tube apparatus for a gas emission sample container which effectively prevents stratification of the gas within the container by drawing gas equally from all parts of the sealed container. It would also be desirable to provide a fitting and tube apparatus for a gas emission sample container which minimizes wrinkling of the sealed container when empty thereby reducing fatigue of the container and enabling more tests to be performed using the same container. Finally, it would be desirable to provide a gas emission sample container which may be constructed of thinner, flexible sheets, while at the same time providing the desired sealing features of previously devised containers.